PID2022-138692NA-I00 - Paola Fuentes Claramonte

Neural correlates of delusions in schizophrenia: a review of the main theories using fMRI

Delusions constitute one of the most important symptoms of schizophrenia; however, both the psychological processes and and brain functional abnormalities that underlie them remain poorly understood. This project aims to examine, using functional neuroimaging (fMRI), three current proposals related to the origin of delusions.
We will examine Kapurs aberrant salience (currently the most influential approach) using a dynamic monetary reward task that can be used to generate a measure of reward prediction error (RPE). RPE is the crucial component of reward processing for the aberrant salience theory, but has been Little examined in schizophrenia and les in relation to the symptoms of the disorder. We will also examine Friths proposal that an impairment in theory of mind and/or other aspects of social cognition underlies referential and persecutory delusions using an fMRI-adapted task where participants view scenes involiving social interactions that require theory of mind to understand the events portrayed. Finally, we will examine a recently reformulated versión of Garety and co-workers proposal that deluded patients show a pathological tendency to jump to conclusions underlies delusions: the original version of this theory proposed that jumping to conclusions reflected a probabilistic reasoning bias, but was well supported empirically. Currently, Garety argues for a broader abnormality: overreliance on Kahnemans fast thinking (reasoning that is rapid, based on simplifying heuristics and prone to errors) together with together with a reduced likelihood of slow thinking (reasoning that is more reflective and involves careful consideration of evidence), is the important factor. We will use a task sensitive to the two types of reasoning, in which slow thinking is necessary to answer correctly.
We will prospectively recruit two matched samples of schizophrenia patients with and without delusions (N=30 and 30) whose delusions will be evaluated in detail and who will carry out the three paradigms in the scanner. We will also examine a group of matched healthy controls (N=30).

Ministerio de Ciéncia e Innovación

109.375 €